One of the members has a post where he states that, for good image quality and proper focus, the focal length of the field fresnel needs to be longer than the focal length of the triplet. That is the case with the pro lens and fresnels, but not the standard ones Lumenlab sells. Can an experienced Lumenlab member comment on this? Thanks!

Ideally the standard triplet should be used with a fresnel of around 360mm. 330mm is used because it is a very common size and can be fudged by moving the lamp slightly closer to the rear fresnel.

DJ